Asian-Australasian Journal of Bioscience and Biotechnology ISSN 2414-1283 (Print) 2414-6293 (Online)
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Asian Australas. J. Biosci. Biotechnol. 2016, 1 (2), 182-189 Asian-Australasian Journal of Bioscience and Biotechnology ISSN 2414-1283 (Print) 2414-6293 (Online) www.ebupress.com/journal/aajbb Article Identification of potential risk factors for recurrent outbreaks of Infectious Bursal Disease (IBD) in poultry farms of Bogra District, Bangladesh in 2015 SK Shaheenur Islam1*, AHM Taslima Akhter2, Md Abu Sufian3, Md Mehedi Hossain4 and Shovon Chakma5 1,3,4Epidemiology Unit, Department of Livestock Services, Dhaka-1215, Bangladesh 2FAO-Food Safety Program (FSP), Institute of Public Health, Mohakhali, Dhaka-1215, Bangladesh 5Institute of Epidemiology, Disease Control and Research (IEDCR), Bangladesh *Corresponding author: SK Shaheenur Islam, Upazila Livestock Officer, Epidemiology Unit, Department of Livestock Services, Dhaka-1215, Bangladesh. E-mail: [email protected] Received: 02 August 2016/Accepted: 16 August 2016/ Published: 31 August 2016 Abstract: An outbreak investigation was conducted in poultry farms of two Upazilas (Bograsadar & Sherpur) of Bogra district of Bangladesh to identify potential risk factors associated with occurrence of Infectious Bursal Disease (IBD)/Gumboro during February-March 2015. A total of 75 farms were recruited under a cross- sectional study of which 40% (n=30) „infected farms‟ and 60% (n=45) „non infected farms‟ from the 2 Upazilas. The infected farms were included from active and passive surveillance data of two Upazila Livestock Offices and District Veterinary Hospital (DVH), Bogra. The non-infected farms were included by convenient sampling technique from the same areas of the two Upazila. The data were collected from the poultry farms using pretested semi-structured questionnaire. A total of 75 farmers were interviewed of which 87% (n=67) male farmers, 11% (n=8) female farmers with an average age of 38(±9) years. Sixty percent (n=45) famers were rearing Sonali type of bird with a flock size 1554(±745) and 40% (n=30) farmers with broiler type of bird with a farm size 828(±263). Among the infected farms, 86.67% (n=26) farms were infected in Sadar Upazila and 13.37% (n=4) farms infected in Sherpur Upazila. The case fatality rate in Broiler and Sonali were 47.47%, 30.32% respectively with an average 33.26%. The study found that 26.67% (n=20) farms had practiced daily disinfection and 34.67% (n= 26) farms did not allow visitors in the farms. The potential risk factors relating to biosecurity aspects were found significant in this study at level of p≤0.05, were, “not practicing all in all out”(OR= 11.15, 95% CI= 2.03-61.16, p= 0.006), “not practicing cleaning and disinfection daily”(OR=7.92, 95% CI=1.2-52.28, p=0.03), “having partial netting of the farm” (OR= 36.97, 95% CI= 3.40-402.40, p=0.003) along with “inappropriate gap between two production cycle” (OR= 15.40, 95% CI= 2.27-99.57, p=0.005). The results from PE presented that good quality chicks (DOCs), farm bio-security, detection of antibody titerat day 1 in conjunction with implementing proper vaccination schedule to be followed for successful IBD prevention and control at the farm level. In conclusion, proper bio-security measures with strict vaccination protocol should be maintained mandatorily to control of IBD at the poultry farm in this district. Keywords: Infectious Bursal Disease (IBD); Gumboro; poultry; risk factors; Bangladesh 1. Introduction In Bangladesh, the poultry sector emerged during 1980s has been taken its full shape now-a-days. About 7-8 million people directly and indirectly involve in this sector, of which 40 percent are woman. At present, total investment in this sector amounting 25,000 million BDT (Equiv. 350.00 million USD) and that to be ascended up to 50,000 million BDT by 2020. This subsector is being kept as a second in position relating to woman empowerment next to Agriculture sector in the rural economy (WPSA, B, 2015). The country has 261.77 million chickens and 50.52 million ducks. The national consumption by year 2020 of poultry meat and chicken eggs is projected to be 307 thousand metric tons and 5,866 million respectively (anon/ unpublished data). Asian Australas. J. Biosci. Biotechnol. 2016, 1 (2) 183 There are many economic important diseases in poultry in Bangladesh such as New Castle Disease (NCD), Infectious Bursal Disease (IBD) and Duck Plague (DP). Of which IBD is very important one, found almost all commercial poultry rearing districts of Bangladesh. The disease also present in most of the chicken producing countries in the globe. Infection can rarely be avoided, mostly due to the high resistance of its causal agent in the environment, and vaccination is considered the only way to prevent the negative consequences of the disease. Adopting a strategy of a sound vaccination with strict biosecurity measures could prevent the infection at the farm level (Fussel, 1998). The causal agent of Infectious Bursal Disease (IBD) is a virus under a member of the genus Avibirnavirusof the family Birnaviridae. Since the disease may occur in wide range of avian species like turkeys, ducks, guinea fowl and ostriches, the clinical signs solely manifest in chickens. Only young chicken are clinically affected. The severe form of the acute disease found in the age of 3–6-week-old birds is related to high mortality rate. Moreover, a less acute or subclinical disease is common in 0–3-week-old chicken. Since the virus affects on the bursa of fabricius, it cause secondary problem later on. IBD virus (IBDV) causes lymphoid depletion of the bursa, and if this occurs in the first 2 weeks of life, significant reduction of the humoral antibody response may result. Two distinct serotypes of infectious bursal disease virus (IBD) are known to be present. Serotype 1 virus causes clinical disease in chickens younger than 10 weeks. Usually the older chickens show no clinical signs (OIE, 2008). Antibodies are sometimes found in other avian species, but no signs of infection are seen. Serotype 2 antibodies are very prevalent in turkeys and are occasionally found in chickens and ducks. There are no reports of clinical disease caused by infection with Serotype 2 virus (Lasher et al., 1994). Gumboro one of the major threats of poultry farming in Bangladesh and there is none option to prevent IBD without vaccination (Lukert et al., 1997). However, Gumboro outbreaks also found in the vaccinated birds (Lukert et al. 1997, Hafez et al., 2002). In Bangladesh various vaccines against IBD are commercially available. Some vaccines were tested their protection level experimentally giving challenge with IBDV and both significant and insignificant increase of antibody titre were reported (Islam et al., 2005). Some commercially available vaccines became fail to give protection against IBD in a number of commercial poultry flocks. Different determinants are considered to be responsible for Gumboro vaccine failure. It is critical to vaccinate commercial chickens that have maternally antibodies at the optimum time (Tsukamoto et al., 1995). Vaccination during low maternally derived antibody titre shows better immune response than high maternal antibody titre (Giasuddin et al., 2003). Again, the immunogenicity of the virus may fluctuate between strain to strain (Rosales et al., 1989; Abdel-Alim et al., 2001) and the invasive vaccine strains are able to break through higher maternally derived antibody level (Kouwenhoven et al., 1994). Vaccination against gumboro could be suggested after detecting maternal antibody in Day Old Chicks (DOCs) (Lukert et al., 1997). Three types of live gumboro vaccine available in the market are being practicing at the farm level are: mild, intermediate and intermediate plus. All types of vaccines administer through water or ocular route. Gumboro (IBD) is a transmissible disease. The possible risk factors for incursion of Gumboro cases to be considered practicing all in all out, interval between two batches/ production cycle with proper cleaning and disinfection along with other biosecurity measures. The mortality may differ 10%-50% depends on virulent of the virus that could be reduced by early diagnosis as well as proper medication. It is a common problem nowadays in broiler and cockerel farms as continuous changing of batches than layer farms. The mortality in gumboroinfected birds reached highest at the day 3 and then it follows a down ward trends until day 6. The disease may occur some areas in the country in combination with LPAI and NCD. Bogra is a district of northern part of Bangladesh. The district is considered as a poultry hub in the country especially for the meat chicken i.e. Sonali. This type of poultry was developed by cross-breeding between two exotic breeds, Fauomyi (hen) and Rhode Island Red(RIR, Cock) and adapted throughout the country especially in the northern districts of Bangladesh and considered to be moderately as native chicken in Bangladesh that supply major meat in the poultry supply chain of the country(FAO, 2015). The monthly collected secondary surveillance data demonstrated that the disease prevails in this district throughout the year. The recurrent outbreak of Gumboro (IBD) in this district create further obstacle to fulfill the national demand of meat. Since there are a very limited study was conducted in this district to explore the possible risk factors responsible for the outbreaks, the present study will explore situation in this regards. That streamlines to underscore potential risk factors relating to IBD outbreaks in this district that could be addressed the actual disease burden. Asian Australas. J. Biosci. Biotechnol. 2016, 1 (2) 184 2. Materials and Methods 2.1. Study area and study design Bogra Sadar and Sherpursub districts of Bogra District, Northern part of Bangladesh (Figure1) were selected to conduct the investigation of IBD outbreaks in poultry during a period of February-March 2015.